How to set up shader materials with main node Principal BSDF
The glTF format has a different material model from Blender, and does not support arbitrary nodes.  It uses a principled PBR model powered by textures and uniforms.
For some materials, it's possible to use the Blender Cycles &quot;Bake&quot; panel to render a complex node graph to a texture atlas.  This allows such a material to be used even on lighter-weight mobile rendering clients that wouldn't normally support arbitrarily large numbers of shading nodes.
For complete usage instructions, see the Blender Manual on glTF.